Kurzsignale
The Short Signal Code, also known as the Short Signal Book (German: Kurzsignalbuch), was a short code system used by the Kriegsmarine (German Navy) during World War II to minimize the transmission duration of messages.
Description
The transmission of radio messages had the potential risks of revealing the submarine's presence and direction; if decoded the content was also revealed. Submarines need to provide information, mostly in standard form (position of convoy to attack and of submarine, weather information), to their bases. Initially Morse code transmissions could be used. To inhibit detection, the duration of messages needed to be minimised; for this, Kurzsignale short-coding was used. To prevent interception, messages needed to be encrypted by the Enigma machine. To shorten transmission even further, the message could be sent by a fast machine instead of a human radio operator. For example, the Kurier system – not implemented in time – decreased the time to send a Morse dot from around 50 milliseconds for a human to 1 millisecond.
Short Signal book
The Kurzsignale code was intended to shorten transmission time to below the time required to get a directional fix. It was not primarily intended to hide signal contents; protection was intended to be achieved by encoding with the Enigma machine. A copy of the Kurzsignale code book was captured from
Radio direction finding
Aware of the danger presented by
Conventional RDF needed about a minute to fix the bearing of a radio signal, and the Kurzsignale protected against this. However, the
The fully automated burst transmission Kurier system, in testing from August 1944, could send a Kurzsignal in not more than 460 milliseconds; this was short enough to prevent location even by huff-duff and, if deployed, would have been a serious setback for Allied anti-submarine and code-breaking activities. By late 1944 the Kurier program was a top priority, but the war ended before the system was operational.[3]
Short Weather cipher
A similar coding system was used for weather reports from U-boats, the Wetterkurzschlüssel (Short Weather Cipher). Code books were captured from U-559 on 30 October 1942.[4]
References
- ISBN 978-1-59114-807-4.
- ^ Rijmenants, Dirk. "Kurzsignale on German U-boats". Cipher Machines and Cryptology. Retrieved 2016-11-21(The article gives full details and examples of Kurzsignale and Wetterkurzschlüssel encoding)
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: CS1 maint: postscript (link) - ^ Aircraft of World War II: thread August 19, 1942
- ISBN 978-0-684-85932-3.